Feed helix



Dec. 27,1949 c. L. WILLARD ETAL,

FEED HELIX Filed Sept. 2, 1947' .5. g m 0 w a AA "H WW/LM I. L a Ra A 5a Patented Dec. 27, 1949- UNITED STATES PATENT OFFICE FEED HELIX Cal-113. Willard and J Jack Willard,

. Lynwood, Calif. Application September 2,1947, Serial No. 771,646

3 Claims. 1

This invention relates to mixing drums and more particularly to themeans .within such drums for feeding material into or dischargingmaterial from the same.

An object of the present invention is to provide a drum of the characterindicated and embodying material-feeding means, that is designed toobviate clogging of said drum particularly when the same receivesmaterial, such as aggregate.

For discharging cement or concrete, a mixing drum is conventionallyprovided with one or more helices which urge such mixtures outwardlywhile said drum is being rotated. The hand of these helices is inaccordance with the direction of rotation of the drum. However, forfeeding aggregate into'the drum to become a cement or concrete mixture,the hand of the helices remains the same but the drum rotation isreversed, and in practice it is found that such aggregate does notreadily feed into the drum heretofore used as rapidly as desired withoutthe opening thereof becoming clogged.

Accordingly, another object of the invention is to provide eflicientdischarge means, in a mixing drum which also efiects rapid feed orintake of materials to obviate clogging of the drum opening.

Our invention also has for its objects to provide such means that arepositive in operation, convenient in use, economical of manufacture,relatively simple, and of general superiority and serviceability.

The invention also comprises novel details of construction and novelcombinations and arrangements .Of parts, which will more fully appear inthe course of the following description. However, the drawings merelyshow and the following description merely describes one embodiment ofthe present invention, which is given by way of illustration or exampleonly.

In the drawings, like reference characters designate similar parts inthe several views.

Fig. 1 is a side elevational view of a mixing drum embodying features ofthe present invention.

Fig. 2 is a partly broken end view as seen from the right of Fig. 1.

Fig. 3 is a detail view of a helical sec'tion employed in theconstruction.

' Y REISSUED 2 JAN 21951 The present invention is an improvement of theinvention disclosed in our application entitled "Portable concretemixer," Ser. No. 672,364, and filed May 27, 1946, now abandoned.Reference is made to said application for the general environment of themixing drum shown in the accompanying drawing. In said drawing, a drum 5is supported at one end in a bearing 6 and at the other by rollers I forrotation about its axis by a drive to a sprocket wheel 8. Said drum ispreferably mounted so that its closed end! is lower than the opening inthereof at the other end and is thereby supported at an angle to thehorizontal. No matter how otherwise formed, the drum, at the open endin, is conically formed as at H being smallest at said open-end whichis, therefore, generally restricted in size with respect to the drumbody l2.

Assuming the drum to have clockwise rotation, the same is provided witha feed helix II that extends for at least 360 and preferably more and isformed to be right-handed and, therefore, efllciently serves, duringclockwise rotation of the drum, to urge a mixture therein outwardlythrough opening it. For a counter-clockwise rotating drum, the helixshould be of the other hand.

When the drum is to receive aggregate throug its opening I0, it isrotated in the opposite direction and said helix will draw saidaggregate into the drum. However, because of the dry nature I 'of thematerials comprising the aggregate, the

openings in the drums heretofore in use, in practice become cloggedsince the helix is insuflicient to draw the aggregate inward at a rapidenough rate. Further, the end of the helix in such a drum, adjacent saidopening, acts to divert some of the material to fall outside of thedrum.

According to our invention, to obviate the above faults, the helix [3,at its end I as it approaches opening I0, is gradually reduced in width.This reduction of the end of the feed helix serves to eliminate thefault of diverting material as stated above. In order to increase thecapacity of the drum to receive dry aggregate, one or more helicalsections l5, similar in form and design to the helix end I4, is providedin symmetrical arrangement to provide a plurality of feed elementsserving to draw material rapidly intothe drum.

Each section I is formed with a relatively narrow end l6 adjacent toopening in so that the same is not blocked thereby, and with a graduallywidened portion terminating at II at an intermediate point of conicaldrum part II.

It will be noted that by our present arrangement the overflow of thenarrow portion of one helix, during discharge of aggregate is caught bythe next helix following. Each of our helices tapers down in width toabout one-half /2) of the wider end of same, the narrower width being atthe opening of the drum. For loading, the reduced ends of our helicesleaves a larger clear opening for the stream of aggregate to enter andto fall far back into the mixer drum and not on to the ground, and stillthe speed of discharge is not reduced. Since the reduced ends II and illof the helices II and I! are about one-half the width of the wider innerends, the same each hasa proportionally smaller capacity to conveymaterial outward oi' the drum. However, the sum of the widths of saidnarrow ends is equal to or greater than the width of the inner portionof helix l3. Consequently, during discharge, the aggregate brought byhelix I3 toward opening III will, in part, fall from the narrowing endI! because of the reduced width thereof. Ordinarily, such dislodgementof aggregate would fall back into the drum and the discharge capacitywould be materially reduced. The helical sections IS, in thisconstruction, catch such spillage and feed the same outward. It will beseen then that the reduced ends I4 and it have a discharge capacity atleast equal to the feed capacity of the wider or main portion of helixI3.

While we have illustrated and described what we now regard as thepreferred embodiment of our invention, the construction is, of course,subject to modifications without departing from the spirit and scope ofour invention. We therefore, do not wish to restrict ourselves to ourparticular form of construction illustrated and described, but desire toavail ourselves of all modiflcations that may fall within the scope ofthe appended claims.

Having thus described our invention, what we claim and desire to secureby Letters Patent is:

1. In a mixing device, a drum arranged on a fixed inclined axis andhaving a reduced open end above the closed end thereof, said drum beingadapted to be selectively rotated in both directions, a helical bladeextending between said ends around the inner face of the drum for atleast 360, the end of the blade adjacent .the open end of the drum beingprogressively reduced in width toward said open end to reduceobstruction to material entering into the drum while the same is rotatedin one direction, said blade, including its reduced end, being adapted,upon rotation of the drum in the other direction, to discharge materialfrom the. open end, and at least one intermediate helical blade oflesser length than the mentioned helical blade disposed in the reducedend of the drum and also being progressively reduced in width towardsaid open end to catch material spilling from the first-mentioned bladeto discharge the same during rotation in one direction of the drum andto draw said material into the drum during rotation in the otherdirection of the drum, the sum of the widths of the reduced ends of allof the blades being at least equal to the width of the widest portion ofthe first-mentioned helical blade.

2. In a mixing device, a drum arranged on a fixed inclined axis andhaving a reduced open end above the closed end thereof, said drum beingadapted to be selectively rotated in both directions, a helical bladeextending between said ends around the inner face of the drum for atleast 360, said blade being of substantial width from the closed end ofthe drum to a point nearer to but spaced from the open end thereof, theend of the helical blade extending from said point to the open end ofthe drum being progressively reduced in width toward said open end toreduce obstruction to material entering into the drum while the same isrotating in one direction, said reduced end of the blade, thereby havinga smaller capacity to convey material to the drum opening than has thewider portion thereof when the drum is rotating in the oppositedirection, and one helical blade section having a length approximatingthat of the progressively reduced end portion of the helical blade andpositioned in the drum similarly to the position of said reducedportion, said helical blade section being progressively reduced in widthsimilarly to said reduced end portion of the helical blade, the sum ofthe widths of the reduced ends of both the blade section and the reducedend portion of the blade being at least equal to the width of thatportion of the latter blade that is inward of the mentioned point of thedrum, whereby material conveyed by said inward portion toward thereduced end portion thereof, upon dislodgement from said reducedportion, is caught by the blade section, and whereby both said reducedends effect discharge of material in amounts substantially equal to thatconveyed by the inward portion of the helical blade. I

3. In a mixing device, a drum arranged on a fixed inclined axis andhaving a. reduced open end above the closed end thereof, said drum beingadapted to be selectively rotated in both directions, a helical bladeextending between said ends around the inner face of the drum for atleast 360", said blade being of substantial width from the closed end ofthe drum to a point nearer to but spaced from the open end thereof, theend of the helical blade extending from said point to the open'end ofthe drum being progressively reduced in width toward said open end toreduce obstruction to material entering into the drum while the same isrotating in one direction, said reduced end of the blade, thereby,having a smaller capacity to convey material to the drum opening thanhas the wider portion thereof when the drum is rotating in the oppositedirection, and two helical blade sections in the drum each having alength approximating that of the progressively reduced end portion ofthe helical blade and uniformly spaced from each other and from saidreduced end portion, each helical blade section being progressivelyreduced in width similarly to said reduced end portion of the helicalblade, the sum of the widths of the reduced ends of both blade sectionsand of the reduced end portion of the blade being at least equal to thewidth of that portion of the latter blade that is inward of thementioned point of the drum, whereby material conveyed by said inwardportion toward the reduced end portion thereof, upon dislodgement fromsaid reduced portion, is caught by one or both of the blade sections,and whereby said three reduced ends eifect discharge of material inamounts substantially equal to that conveyed by the inward portion ofthe helical The following references are of record in the the 01' thispatent:

Number 6 UNITED STATES PATENTS Name Date Ransome "Nov. 12, 1907 RansomeJan. 17, 1911 Temperley May 11, 1926 Robbins Nov. 18, 1930 Shafer, JrJune 9, 1942 Peters Jan. 11, 1944

